What is Difference Between Spermatogenesis And Oogenesis?

Spermatogenesis vs Oogenesis

The main differences between oogenesis and spermatogenesis

Although in both processes the animals generate the sexual cells or gametes, the oogenesis and spermatogenesis differ by the type of the gametes formed, the number of gametes formed, the difference in the structure of a reproductive organ, and their time of occurrence in males and females.

If you want to know more, read on!Difference Between Spermatogenesis And Oogenesis

What are the differences between ovogenesis and spermatogenesis?

  • The most important difference is that oogenesis is a process that takes place in the ovary while spermatogenesis takes place in the testicles.
  • The second important difference lies in the properties of each gamete. The oocyte accumulates more vital during oogenesis since its function is to wait for the arrival of sperm in the fallopian tubes. Instead, the sperm minimizes its cytoplasm, generates motility structures and enzymes to remove the barriers that protect the egg and make fertilization more difficult.
  • During oogenesis, the ovule appears surrounded by numerous layers and membranes that have different functions (mechanical protection, protection against fertilization by more than one sperm cell, etc.). These layers also appear and disappear during their maturation. In the case of spermatogenesis, the sperm is only surrounded by a membrane, the cytoplasmic membrane.
  • Spermatogenesis is produced from an embryonic diploid cell called spermatogonia, while the ovule is generated from a diploid and also embryonic cell called ovogonia.
  • During oogenesis, ovogonia results in only one secondary oocyte, which can be fertilized while, during spermatogenesis, spermatogenesis gives rise to four mature spermatozoa, which can fertilize four oocytes. We can say that, in the case of the male, the quantity predominates while in the female the quality predominates.
  • Related to the above, we can see a great difference in the process of meiosis that takes place in spermatogenesis and oogenesis: in spermatogenesis, the meiotic divisions are symmetric, that is, all the cells generated have the same amount of cytoplasm; on the other hand, in oogenesis, the meiotic divisions are asymmetric since almost all the cytoplasm will pass to the next oocyte and only one part is carried by the polar corpuscle.
  • During the oogenesis, a byproduct, the polar corpuscle, is formed and atrophied and eliminated. In spermatogenesis, however, no byproduct is produced. We can say that, in this case, the male is more conservative.
  • In spermatogenesis, the sperm must undergo a very large cell differentiation process to acquire the necessary structures for motility, penetration of the pellucid zone, etc. while, in oogenesis, the ovule does not undergo very drastic changes in its shape.
  • The female is born with a certain number of oocytes, which will ripen throughout her reproductive life. When these are over or their hormones order them to stop maturing, menopause occurs and the female reaches the end of her fertile stage. In the case of men, spermatogenesis occurs practically throughout life, and men begin to produce sperm from puberty and never stop producing them or do so when they are very old.
  • The oogenesis begins during the seventh month of embryonic development, while spermatogenesis begins to occur periodically when the male reaches puberty.
  • In oogenesis, we observe two periods of latency while spermatogenesis is a continuous process, in which there are no stops. The first one, called diction, begins during embryonic development and does not end until it reaches puberty; the second occurs in each menstrual cycle and is one in which the secondary oocyte stops its division in the metaphase of the second meiosis (metaphase II) and is expelled through a process called ovulation.
  • The spermatogenesis is completed while the sperm is inside the testicle. However, the ovule ends its maturation outside the ovary since the completion of meiosis II occurs outside the ovary.
  • The oogenesis only fully completed if fertilization while spermatogenesis is fully completed, it will not occur or fertilization of the egg.
  • When oogenesis ends, the result is only one ovule while, in spermatogenesis, thousands of sperm are generated at once. This is another example in which the male prefers to generate much sperm, from which the best one (the one that will arrive or will fertilize the secondary oocyte) will be selected.
  • In the case of humans, spermatogenesis has an approximate duration of between 62 and 75 days while, in the case of women, the menstrual cycle (which is what determines how often women can reproduce) lasts 28 days. Around day 14 of the cycle, ovulation occurs and fertilization has to take place between 24 and 48 hours after it.

What is ovogenesis?

The oogenesis is the set of processes that lead to the formation of female gametes, ova. The oogenesis begins during the embryonic development of the woman or female from a germ cell. Oogenesis begins in the ovary and ends in the fallopian tubes if there is fertilization. First, the germ cells of the ovary undergo cell division by mitosis, leading to oogonia.

Then, these oogonia suffer a division by meiosis, which remains stopped (arrest) in prophase I until puberty. This cell is called the primary oocyte and remains deployed. The primary oocyte for its part undergoes second meiosis, which stops in prophase II until fertilization occurs. This cell is a secondary oocyte (haploid cell) is released in ovulation and they look very similar to that of a mature ovum.

Minutes after fertilization, the second meiosis is completed and we are already facing a mature ovum capable of joining its DNA with that of the sperm to generate the zygote.

What is spermatogenesis?

The spermatogenesis is the set of processes that lead to the formation of male gametes, the spermatozoa. Spermatogenesis begins at the puberty of men from a germ cell and takes place in the epididymis, a duct found in the testicles.

First, the germ cells of the epididymis undergo cell division by mitosis, resulting in spermatogonia. Next, the spermatogonia undergo a division by meiosis and some slight modifications and two primary spermatocytes are generated. Each of these first spermatocytes undergoes second meiosis, which results in the formation of two spermatids (haploid cells that look very similar to that of a sperm cell).

Finally, the spermatids undergo a series of modifications, which serve to allow the sperm to move and fertilize the ovule in a more effective way.

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